From Longman Dictionary of Contemporary Englishgrousegrouse1 /ɡraʊs/ noun 1 
[countable, uncountable] (plural grouse)HBB a small bird that is hunted and shot for food and sport, or the flesh of this bird the grouse shooting season roast grouse2 [countable] informalCOMPLAIN a complaint His main grouse is that he isn’t paid enough.
[countable, uncountable] (plural grouse)HBB a small bird that is hunted and shot for food and sport, or the flesh of this bird the grouse shooting season roast grouse2 [countable] informalCOMPLAIN a complaint His main grouse is that he isn’t paid enough.Examples from the Corpus
grouse• Meanwhile, a grouse landed in an apple tree beside me, then flew down to the ground and walked away.• It is the same for sage grouse.• This recipe works well with any of the small birds-quail, squab, grouse.• Throughout the day the grouse drums in the woods, and the woodcock performs its exuberant ritual at dawn and dusk.• As we walked, grouse rose from the heather, calling out in alarm, .grousegrouse2 verb [intransitive] informalCOMPLAIN to complain about something SYN moangrouse about I haven’t really got much to grouse about.→ See Verb tableExamples from the Corpus
grouse• "Everything tastes the same, " George groused.• So Brick, who had at first dismay, now had no room to grouse.• He nagged at Fritz, he groused about the dull food, he broke some plates against the wall.• There was some grousing about the way the game had gone but, for the most part, we were pretty good.• They do not have too much to grouse about, though: the family's income is about 1,600 yuan a month.• Stuyvesant, grousing, harassed the exiles and hampered their efforts to buy homes and cemetery plots.Origin grouse1 (1500-1600) Perhaps from Latin gruta, name of a type of bird hunted for food grouse2 (1800-1900) Perhaps from Old French grouchier; → GROUCH1 